The shares of ICI Australia Ltd. plunged yesterday after the company's parent, Imperial Chemicals Industries P.L.C., said on Wednesday that it would sell its 62.4 percent stake in its Australian subsidiary. The sale, which contradicts earlier speculation the British parent would buy out minority shareholders in ICI, comes as ICI P.L.C. prepares to buy the specialty chemicals of Unilever N.V. for $8 billion in cash.

ICI Australia said that it expected the share sale to begin in July and that it would probably change its name when the sale was complete. ICI Australia's shares fell $1.09 (Australian), to $11.35 a share on the Australian Stock Exchange.